The list of school supplies he needed was online. We usually have extra stuff on hand at home but this year our stash has dried up and we spent about $20 for everything on his list.
He tried on all his jeans and pants and weeded out too small items. We donated several pair and put several pair in the grow-into box and he still has plenty of clothing. His backpack from last year is still in great condition and I found a new lunch box over the summer so I think he's set. I have brand new shoes in the next couple of sizes up that I've been buying at the thrift store over the last year so he'll have a new pair when he starts school. He's pretty hard on shoes so I try to get 2 pair in each size so they can be replaced partway through the year.
He doesn't start school until September but it's done and out of the way now.